Ferrofluids are liquids in which ferromagnetic particles are suspended. Ferrofluids are currently pumped using conventional mechanical fluid pumps. These conventional pumps permit only limited control of the flow rate and allow the fluid to be pumped in only one direction. In addition, conventional pumps have moving pump components located in the path of fluid thus it may be necessary to penetrate the fluid boundary during repair. Penetration of the fluid boundary may be impractical if the pump is in a zero gravity environment, such as space, or when the fluid is contaminated such as when the pump is used in nuclear applications.
Mechanical pumps are not well suited for pumping fluids having both liquid and gas phases, since the pressure head developed by the pump drops to zero at small volume fractions of vapor.
Experiments have shown that ferrofluids can be set in motion by a magnetic field. In particular, the thesis of Tae In Choi entitled: "Ferro Fluid Motion in a Rotating Magnetic Field", University of Florida, 1980, noted that magnetic fields caused ferrofluids contained in a vessel to circulate in one direction towards the center of the vessel and in the opposite direction near the outer portion of the vessel.
A series of articles written by O.A. Glazov discuss the theory of the use of a moving magnetic field to set in motion magnetic fluids. These articles are: Entrainment Of a Ferromagnetic Suspension By a Traveling Magnetic FIELD; "Magnetohydrodynamics" July-Sept. 1973, p.p. 395-396; Role OF Higher Harmonics In Ferrosuspension Motion In a Rotating MAGNETIC FIELD "Magnetohydrodynamics" Oct-Dec. 1975, p.p. 434-438; and Setting a Ferromagnetic Liquid INTO Motion With a Running Magnetic FIELD "Magnetohydrodynamics" Oct-Dec. 1976 p.p. 400-404 O.A. Glazov.
Theoretical calculations have shown that a magnetic particle and a magnetic liquid can be moved in a manetic field. The rotation of a body of ferrofluid has been achieved by the use of a rotating magnetic field. The likelihood that using a moving magnetic field could cause flow of a ferrofluid in a flow channel such as a tube has not been established. Therefore, although it appears likely that a moving magnetic field could effect the movement of a body of fluid containing magnetic particles, the utility of such a concept is uncertain.
Some ferrofluids have properties which make them suitable for use as heat transfer fluids, thus a magnetic pump, if practical, could be used in heat transfer applications.
There is no teaching in the prior art which predicts the characteristics of the electric field needed to move a ferrofluid in a flow channel, the design of a pump employing such a concept, and the operating conditions of such a pump.
There is a need for a pump that could utilize a magnetic field to produce motion in ferrofluids so as to produce a pumping of the fluids.